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M50/S50/S52 E30 Conversion

Discussion in 'E30 (1984-1993)' started by MGarrison, Jan 14, 2009.

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    az3579

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    I was checking up on prices of the E34 M5 master cylinder and realized something. The thread I read about this says to use the E34 M5 for the 325ix booster and the E32 735iL cylinder for the modified 320i booster. Aren't the M5 and 735iL masters the same? The exact quote was:

    What is this 25mm I see? Aren't these two cylinders the same? According to realoem they are, so I wonder why they listed them separate depending on the booster used...
    Part # I have for the M5 master cylinder is 34 33 1 156 978

    z31maniac guest

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    I'm telling you. Just order the THR or Zionsville booster and keep your stock master cylinder/reservoir setup. With the E28 M5 mounts you don't have to worry about shaving down fins on the intake manifold.

    And 25mm MC, vs stock 21.4mm I think, is going to increase your pedal effort by around 22% (if I remember Lee's calculation). A new master cylinder is going easily cover the cost of the THR booster. Even if the double chamber booster picks up some of the slack, you've now taken your range for brake modulation into a smaller range. IE, a smaller distance between lock-up/hard braking for example.

    The only reason I went ahead and bought a new stock E30 master cylinder was because of all the other stuff I've been replacing.

    Oh and another big one. Yank out the E36 starter/fuse box wiring wires (it will be two big red wires coming out on the driver side of the harness) and use the E30 starter wire. Once you yank out the E36 stuff you can use the stock E30 starter wire that connects to the distribution block on the passenger side, you can even run it through the harness cover to keep it clean looking. Then run the two wires out of the E30 fusebox back over to the distribution block on the passenger side.

    There are a some threads on R3V about this. Even one I started that will clear up all the wiring on the passenger side of the car.
    • Member

    az3579

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    Just looked into the price of the Ziosnville booster and it would be pretty close to the price of a new master cylinder and a used booster, BUT, it would still be about $30 cheaper. I take it there are NO modifications involved if I use this booster as opposed to using the ix/M5 combo?

    (Treehouse Racing has the booster for significantly more, BTW)

    z31maniac guest

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    ^THR was $30 more when I bought mine about 2 months ago.

    moose, should the Tach be bouncing around when trying to start, it isn't.

    I jumped the fuel pump relay and that didn't get fuel either. I suspect the DME isn't getting a ground/power. Is that PIN 1 to check the harness for power?

    Damn this is frustrating. It sure is turning over strong!
    • Member

    az3579

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    They're not the same, are they?
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    • Technical Service Advisor

    mooseheadm5

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    If you jump the fuel pump relay and you cannot hear the fuel pump, you have a blown fuse or something is not wired up properly. Jumping it out will make the fuel pump run whether or not the key is on or the DME is hooked up.

    If you mean that you jump it out and it still won't start, then you need to try to start it with carb cleaner. If that doesn't work then you don't have spark either and you need to check things out. You need to get a multimeter so you can go through the power and ground tests as per the Bentley manual.

    z31maniac guest

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    *blushes* For some reason there was no fuse in the fuse box for the fuel pump. Put one in and the engine immediately roared to life and settled into a nice idle, however.

    The motor starts right up, idles solidly and seems to run good. A quick test drive around the neighborhood.....I made a small stab at the throttle, while going straight, in 1st gear about 3k and was greeted with two nice black marks and sliding *** end, so the motor seems to be running strong.

    1. Brake pedal is soft, I'm sure it just needs to be bled again since all 4 calipers are new as well as the master cylinder. However, when at a stop and pressing the brake pedal it seems as though the motor reacts with a slight dip in RPMs when the pedal is pushed. Some sort of weird vacuum issue? (I did just remember I don't have that little check valve inline between the booster and manifold, do you have one to sell?)

    2. The car seems to be burning A LOT of oil. I realize it hasn't ran in a long time, but still. I'm running 10-40 Royal Purple. I'm thinking the PCV is gunked up, and I've read that a bad PDV can cause excessive oil consumption. Basically if the engine is running blue smoke is coming out, more throttle application = more smoke.

    I'm really hoping it isn't worn rings/valve guides, but the motor seems to be running really well for that.

    It's going to the shop on Tuesday for a compression test and a few other things.

    Praying to god the engine isn't tired, the salvage has said they would warranty any problems, but I don't want to **** with this headache again.
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    mooseheadm5

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    1. You should do a full bleed again.
    That check valve is just there to keep vacuum in the booster and won't affect normal operation at idle, though you should really get one (sorry, I don't think I have a spare right now.) If you have a vacuum leak, however, especailly if the leak is in the booster diaphragm, it can cause this idle issue. Do you hear a hissing coming from under the dash with your foot on the brake? Really, it probably is nothing, though.
    2. If the motor sat, it could have a stuck ring. Check your plugs to se if one cylinder is particularly bad. About the PCV- what motor and intake setup are you running? If OBD1 intake setup, the PCV is probably not your problem. Is there smoke? Is there an oil slick on your bumper yet? I helped a friend S50 swap a 525 wagon and his burned a ton of oil. Turned out the "perfect" S50 he got had a broken ring land. A compression and leakdown test would show that issue.

    z31maniac guest

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    Going to take it to the shop tomorrow to have the brakes bled again. We close on a house on Friday so I'm out of time to get this done on my own.

    2. Is there anyway to "unstick" a ring? I'm really, REALLY hoping it's not something like that or the broken ring land. If that was the case would the motor still run fine? OBD-I PCV on the OBD-II valve cover, connected how they how it on the E30 DOHC WIKI page with a small piece of hose.

    There is quite a bit of blue smoke coming out of the exhaust. And the more throttle you give it the more smoke comes out. But it seems to be running good, steady idle, seems to rev well when given the throttle. Although once you let off it does seem to take a second for revs to fall back down to idle, so I'm thinking there may be a vacuum issue.

    I'm going to tell the shop tomorrow what my issues are and see if they can determine if it's a PCV/Vacuum issue or if it's something more sinister. Because there are a couple of other little things I need to take of, but they won't be worth doing if the engine has to come back out.


    If there is a problem with the motor,
    1. I'm going to be sorely, sorely ****ed at the 'yard I purchased it from.
    2. We will get to see if they are going to stand behind the word the owner of the 'yard gave me. Since I think technically I'm just out of the 6 month warranty from purchasing the engine.

    He gave me his word that if there was a problem, since he knew it would be a while before I ran from when I purchased it, he would take care of it. Under the warranty period or not.

    I'm hoping for the sake of my own sanity, it isn't a problem with the engine. If I have to go through all that again, ugh, I don't even want to think about it.

    z31maniac guest

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    Both Zionsville and THR use the E21 booster I believe. Zionsville warranties it as well, but said they can't test the booster. THR said they do test the booster and still warranty it.
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    mooseheadm5

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    To unstick a ring, you can pull all the plugs and pour in a 50/50 mix of ATF and acetone. Let it soak, turn it over by hand a few times, let it soak. It may help, it may not, but either way you will need to change the oil, and it will without a doubt smoke for a bit when you start it up again. Of course, you would not consider starting it up until all the mix makes it out of the cylinders. As I said, a leakdown and compression test will tell you all you need to know. It doesn't sound great, but it could be a stuck ring or a pcv issue. You can rule out a PCV issue by disconnecting the PCV hose from the intake. Plug the intake end and let the other end vent to atmosphere. If the smoke stops soon after, the PCV is to blame. The smoke may not stop instantly due to accumulated oil in the intake. Have you pulled the plugs?
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    az3579

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    Sounds good. I'd rather buy it pre-modified, even if it costs a bit more, so that I don't have to worry about finding someone who knows how to do it.

    I will get that at the end of the week when my next "allocation" comes around.




    EDIT: Actually, the week after this Friday because I have to dump $300 on the upcoming HPDE that I want to attend. :D

    z31maniac guest

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    moose, I realized the test about the PCV yesterday. Unplugged it and ran the engine fir about 25-30 seconds and got just a few puffs of blue smoke instead of the clouds I got the day before.

    Going to pick up a new PCV and hose today and will fix the coolant leak tomorrow, hopefully have it on the road aligned and with an exhaust by this weekend.
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    mooseheadm5

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    Sweet! You will continue to have some smoke, but as long as you get that fixed and the smoke tapers off, you are golden.

    Pics or it doesn't exist :)
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    az3579

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    [sigh]

    Perhaps in a month or two I could also post some pics of that bad boy in there. lol

    z31maniac guest

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    Fixed the coolant leak, had the brakes/clutch rebled, exhaust built, etc.

    Wow is the car QUICK! And my BBK hauls the car down with FEROCITY, really amazing, pedal feel is fantastic. Can't wait to get some sticky tires and ditch the cheapies that are on it now.

    It's amazing how much oil the PCV was dumping into the intake manifold, there was standing oil in it right behind the throttle body.

    ACM1899 guest

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    I wanted to ask you pro's something? Im not a DIY guy but in the near future (2-3 years) i would like to get a old e30 coupe or sedan and put in a e36 m3 engine into it. I was wondering if i got all this work done and i needed to rebuild the m3 engine how much would this cost?

    A ruff estimate will do just fine for the moment. Thanks again..
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    mooseheadm5

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    It would cost a lot if you paid someone else to do it. It will still cost thousands if you do it yourself. Bank on dropping at least 5k including parts, maybe more if you don't buy a whole package of things at once.

    ACM1899 guest

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    Thanks for the quick reply MH. Im going to do my first DIY this month and open up my passenger seat to see if the gear is broken to make the seat recline.

    What are the M50/S50/S52 specs?
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    mooseheadm5

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    I'll save you a a little downtime on the seat- if the motor moves, it needs the gear. Order them from odometergears.com.

    Specs? What do you mean?

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